MB-13863 Add missing primary index check in rollback
MB-13863 Add missing primary index check in rollback

primary indexes don't have a back index. rollback needs to
skip that.

Change-Id: Ibc1a0ab3fad3523f637902d10cb844b0158e67ec

jchris/indexing,jchris/indexing,jchris/indexing,jchris/indexing